In the limp material assembly field, individual segments are cut from sheet material, and these cut segments are then delivered to a staging area to be assembled in various combinations (hereinafter "preforms"), perhaps with other materials. These preforms are then processed into various products and articles.
Although cutting and sewing generally is an old and well-known art, there is a continuing need to adapt to the special features of newly developed limp materials. Many of these new materials are light weight and delicately woven, yet are tough and durable, such materials include specialty synthetics used in outerwear, or epoxy-graphite materials ("composites") used in sporting goods, radomes, and the like.
More particularly, in the construction of composite parts by resin transfer molding processing, a preform is made of layers of dry woven composite materials such as fiberglass or carbon fibers. This preform is then put in a mold and injected with resin to make the finished part. These preforms can be difficult and time consuming to make. On one hand, the preform must be precisely assembled for quality control reasons, and on the other hand, composite materials tend to be loosely woven and tend to distort and unravel at the slightest of handling. There is therefore a need for improved means for removing individual cut segments from a cut sheet of delicate, limp material, while both maintaining the shape of the removed segment and without disturbing both the remaining cut segments and the scrap.
Presently known equipment and processes do not adequately address this material-handling issue in a cost-effective manner. Yet obtaining cost-effectiveness is a high priority in a globally competitive market. Hence any solution must be capable of handling delicate, cut material segments with a minimum of material distortion, and must be able to do so in volume, in a highly repeatable manner, and with a minimum of scrap and waste.
A further problem is noted during handling of impregnated special materials, such as resin impregnated fibers, where the materials have a surface tackiness. Here it is necessary to be able to remove a cut segment from the remaining material without having the remaining material adhere to the picking device. In addition, the picking device must be able to gently unload the picked cut segment and to deliver it to a staging area in a smooth and undamaged condition, notwithstanding such material surface tackiness.
It is therefore an object of the present invention to provide a method and apparatus for automated limp material handling which overcomes the deficiencies of the prior art.
It is a further object of the present invention to provide a method and apparatus for picking up a cut segment of limp material and delivering it to a staging area with the ability of accurate positioning and without distortion of the picked segment.